On Tue, May 19, 2020 at 10:28:41PM -0400, Qian Cai wrote: > > > > On May 19, 2020, at 6:05 PM, Thomas Gleixner <t...@linutronix.de> wrote: > > > > Yes, it's unfortunate, but we have to stop making major concessions just > > because tools are not up to the task. > > > > We've done that way too much in the past and this particular problem > > clearly demonstrates that there are limits. > > > > Making brand new technology depend on sane tools is not asked too > > much. And yes, it's inconvenient, but all of us have to build tools > > every now and then to get our job done. It's not the end of the world. > > > > Building clang is trivial enough and pointing the make to the right > > compiler is not rocket science either. > > Yes, it all make sense from that angle. On the other hand, I want to be focus > on kernel rather than compilers by using a stable and rocket-solid version. > Not mentioned the time lost by compiling and properly manage my own toolchain > in an automated environment, using such new version of compilers means that I > have to inevitably deal with compiler bugs occasionally. Anyway, it is just > some other more bugs I have to deal with, and I don’t have a better solution > to offer right now.
Hi Qian, Shameless plug but I have made a Python script to efficiently configure then build clang specifically for building the kernel (turn off a lot of different things that the kernel does not need). https://github.com/ClangBuiltLinux/tc-build I added an option '--use-good-revision', which uses an older master version (basically somewhere between clang-10 and current master) that has been qualified against the kernel. I currently update it every Linux release but I am probably going to start doing it every month as I have written a pretty decent framework to ensure that nothing is breaking on either the LLVM or kernel side. $ ./build-llvm.py --use-good-revision should be all you need to get off the ground and running if you wanted to give it a shot. The script is completely self contained by default so it won't mess with the rest of your system. Additionally, leaving off '--use-good-revision' will just use the master branch, which can definitely be broken but not as often as you would think (although I totally understand wanting to focus on kernel regressions only). Cheers, Nathan
